The safety and efficiency of axial flow fans and compressors, such as, for instance, gas turbine engines are typically limited, in part, by the performance of the compressors that supply high pressure air for combustion. Gas turbine engines are subject to rotating stall in the compressor section during operation, which is of particular concern to aircraft designers. Stall has a negative impact on the overall performance of the engine including the ability to attain maximum fuel efficiency. As there are no known diagnostic sensors available to the engine operator to predict incipient stall, the engine must be operated with fuel management strategies that maintain the compressor at safe stall margins over a wide range of operating pressures and speeds. Operating the engine at these conservative settings typically prevent the engine from attaining maximum performance and efficiency which can usually only be obtained near conditions of stall at reduced stall margins.
Active management of the incipient stall process would make it possible to reduce the stall margin during operation. However, prior techniques that attempt to successfully manage the stability of the compressor section have used sensors (e.g., Kulite® sensors) that have proved incapable of surviving the harsh operating environments typical of full-scale compressors (e.g., the operating conditions found in jet-engines). In particular, heat and vibration typically contribute to an almost instantaneous destruction of the sensors.